<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var arr = [
            11,12,
            [
                11,23,
                [12,23]
            ]
        ]
        // var str = arr.join()
        // var arr1 = str.split(',')
        // var arr2 = Array.from(new Set(arr1))
        // console.log(arr2)
        var arr3 = []
        function one (arr){
            for(var i=0;i<arr.length;i++){
                if(Array.isArray(arr[i])){
                    one(arr[i])
                }else{
                    arr3.push(arr[i])
                }
            }
        }
        one(arr)
        console.log(arr3)
    </script>
</body>
</html>